Cutters for forming highway paint receiving grooves

ABSTRACT

A ROTATABLE CUTTER TO FORM GROOVES IN HIGHWAYS RECEIVING REFLECTIVE HIGHWAY PAINTS TO INDICATE SEPARATION BETWEEN HIGHWAY LANES. THE CUTTER HAS LONGITUDINALLY SPACED RIDGES NORMAL TO ITS AXIS WITH CONVEXLY CURVED CRESTS, TAPERED SIDES CURVING INTO ELONGATE ROOTS WHICH, PREFERABLY, HAVE INTERMEDIATE CYLINDRICAL SURFACES, THE CREST, SIDE AND ROOT PORTIONS HAVING DIAMOND CUTTING ELEMENTS EMBEDDED THEREIN. ROTATION OF THE CUTTER WHILE MOVING ALONG THE HIGHWAY PRODUCES GROOVES, VALLEYS OR TROUGHS IN THE HIGHWAY OF A DEPTH TO RAPIDLY COLLECT AND DRAIN RAIN WATER AND KEEP IT OFF THE UPPER PORTIONS OF THE REFLECTING SIDES OF THE TROUGH, THE HIGHWAY CRESTS BETWEEN TROUGHS HAVING FLAT SURFACES INSURING VEHICLE CONTROL WHEN ITS TIRES PASS OVER THE GROOVED AREA.

f-Jap, v1'2; 197f1 .HMABVEYETAL 3,554,606

. CUTTERS FO FORMIN HIGHWAY PAINT RECETVING GROOVES IN VE/V Tvc/es. oA/,QLoH/MQBEV ejac/s: C. GLEN/ML United States Patent O 3,554,606 CUTTERS FOR FORMING HIGHWAY PAINT RECEIVING GROOVES Donald H. Mabey and Jack C. Gledhill, Salt Lake City,

Utah, assignors to Christensen Diamond Products Company, Salt Lake City, Utah, a corporation of Utah Filed `Ian. 22, 1969, Ser. No. 793,054 Int. Cl. E21c 37/26; E01c 23/16 U.S. Cl. 299-89 l21 Claims ABSTRACT OF THE DISCLOSURE A rotatable cutter to form grooves in highways receiving reflective highway paints to indicate separation between highway lanes. The cutter has longitudinally spaced ridges normal to its aixs with convexly curved crests, tapered sides curving into elongate roots which, preferably, have intermediate cylindrical surfaces, the crest, side and root portions having diamond. cutting elements embedded therein. Rotation of the cutter while moving along the highway produces grooves, valleys or troughs in the highway of a depth to rapidly collect and drain rain water and keep it off the upper portions of the reflecting sides of the trough, the highway crests between troughs having flat surfaces insuring vehicle control when its tires pass over the grooved area.

The present invention relates to milling cutters useful in forming uniform grooves or troughs in concrete highways, and more particularly to milling cutters for producing grooves or troughs capable of effectively receiving and retaining highway paints which will be visible to vehicle operators in rainy weather or under wet conditions generally.

The present invention is directed to cutters for grooving roadways to designate separation between trathc lanes. The cutters are specifically designed for providing grooves in concrete highways, as described and claimed in the application of Gordon M. Liddle and Frank L. Christensen, Ser. No. 747,692, liled July 25, 1968, for Marked Roadway and Method of Making the Same.

Milling cutters embodying diamond cuttng elements therein are known for performing a cutting action on concrete highways. U.S. Pat. No. 3,306,669 discloses diamond milling cutters that will produce grooves in a concrete highway during a cutting action designed to remove bumps from the highway surface. However, such milling cutters cannot accomplish the functions of the cutters embodying applicants invention, and described hereinafter in this case, since the grooves they form are shallow and cannot drain rain water along the roots of the grooves suiciently for the purpose of leaving exposed surfaces for light reflection above the water level in the grooves. About all the cutters of Pat. No. 3,306,669 could accomplish is to provide a roughened or skid resistant texture in the surface of the concrete highway.

A{By virtue of the present invention, grooves are formed in a concrete highway that are deep enough to trap rain water, draining it along the roots of the grooves or troughs to leave exposed surfaces above the water level for light reflection from the highway paints with which the sides and bottom of the grooves are coated. The cutters produce grooves in which the life of the crest of the ridges between the grooves is prolonged, since an essentially ilat surface is provided that resist lateral or right angle forces that might tend to break the concrete, furnishing a generally tlat surface providing vehicle control when its tires pass over the paint striped area. The strength and enurance of the grooved pavement area is high. The cutters produce grooves in the concrete with upwardly diverging sides so that the highway paint on the sides will be reflected in an 3,554,606 Patented Jan. 12, 1971 ice upward direction and will be readly visible to the vehicle operators. All corners of the cutters are rounded, producing grooves in the'concrete highways in which the bottoms are concavely curved, merging smoothly into tapered sides of the grooves, which, in turn, merge into convexly curved crests of the ridges between the parallel grooves. These convexly curved portions preferably merge into longitudinal llat surfaces at the upper surfaces or crests of the ridges.

Because the cutters form a grooved highway area in the manner just described, such area is self-cleaning, inasmuch as there are no right angle corners for collection of dirt, salt, and road films, which would obliterate or eliminate the highway marking paint. In addition, ice collection in cold climates is greately minimized since the ice forces itself up and out of the highway grooves as it forms and expands. The cutters produce a grooved striped region in which only a minor portion, which, for example, may be about 35%, of the highway painted strip is exposed to automobile tire wear. The radiused longitudinal grooves and ridges provide for better placement and retention of the-reflective beads in highway paint, resulting in a brighter reflectve paint marking. In addition, the cutters produce uniform grooves and intervening ridges in the highway surface of a long, useful life, the cutters themselves being strong and sturdy, and having a comparatievly long life.

This invention possesses many other advantages, and has other purposes which may be made more clearly apparent from a consideration of a form in which it may be `embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIG. l is a perspective view of a small section of concrete pavement, with highway striped areas formed therein;

FIG. 2 is a side elevational view of a cutter apparatus embodying the invention;

FIG. 3 is an enlarged longitudinal section taken along the ilne 3-3 on FIG. 2;

FIG. 4 is a fragmentary section taken along the line 4 4 on FIG. 3;

FIG. 5 is an enlarged section taken along the line 5 5 on FIG. 2;

FIG. 6 is an exploded enlarged fargmentary section of the cutter and the grooves formed thereby in the concrete roadway, the cutter diamonds being omitted for purpose of clarity; and

FIG. 7 is an enlarged fragmentary section of an actual cutter design, with diamonds omitted for purpose of clarity.

As disclosed in the drawings, a milling cutter 10 is provided for forming grooves 11 in a concrete highway 12 of an overall width corresponding to the width of a highway paint stripe which serves to separate and define traffic lanes. Grooves are formed in the highway surface to the desired depth, leaving intervening ridges 13, and such grooves and ridges are then coated with reflective highway paint (not shown) so that the tratlic lanes are readily visible to drivers of vehicles traversing the highways.

The cutter assembly 10 includes an arbor 14 of suitable length mounted on a rotatable drive shaft 15, rotating therewith because of the intervening external and internal meshing splines 16 on the shaft and arbor. The shaft 15 and end portion 17 of the arbor are supported in suitable bearings (not shown) and in the frame of a concrete -grooving machine (not shown). The milling cutter itself includes a sleeve 18, which may be made of steel, to which a matrix body 19 is bonded, the matrix having the longitudinally spaced, circumferential ribs or ridges 20 formed therein disposed normal to the axis of the matrix and sleeve and dening intervening valleys, troughs or grooves 21 therebetween. In effect, the ridges and grooves form hills and valleys, there being diamond cutting elements 22 molded or otherwise embedded in the matrix 19 in a known manner. Circumferentially spaced, 1ongitudinal waterways 23 are provided in the matrix, such waterways following the hills and valleys of the outer portion of the matrix, as disclosed most clearly in FIG. 5. Water or other ushing fluid is used for cleaning and cooling the cutters during its traverse along the highway. It is to be noted that the diamonds 22 are separated from each other and are distributed in a desired pattern over all surfaces of the grooves 21 and ridges 20 so as to perform a cutting action in the concrete, producing the bottom 24 and sides 25 of the grooves 11, as well as the intervening ridge portions 13.

The sleeve 18 and diamond set matrix 19 are clamped to the arbor 14 by a clamp nut 26 threaded on the arbor and engaging a spacer 27, which bears against one end of the steel sleeve 18, the other end of the steel sleeve engaging a friction ring 28 abutting a shoulder or flange 29 integral with the arbor. Accordingly, rotation of the shaft 15 will rotate the arbor 14, sleeve 18, matrix 19 and the diamond cutting elements 22 as an integral unit, while the assembly is moved bodily along the highway surface, so that the rotating cutter 10 can form the grooves 11 therein.

The bottom or root portions 30 of the cutter grooves 21 are much wider than the intervening ribs 20, to form grooves 11 in the concrete surface separated by ridges 13 that are much wider than the grooves therebetween. Moreover, the height R of each cutter ridge is such as to form a desired depth of groove in the concrete surface, which, as stated above, is suicient to effect proper drainage of rain and other waters while leaving the tapered sides of the highway grooves exposed above the water level in the lower portion of the grooves 11. Moreover, there are no right angle corners present in the ridge and root portions of the cutters, corners being curved to form corresponding curves in the concrete surface.

As specifically disclosed (see FIG. 6 particularly) the height R of each cutter ridge 20, which is the distance between its root 30 and crest 31, is about 3/16 of an inch to about 1/2 inch to produce a corresponding depth A of groove in a concrete highway surface. The radius of curvature S of the crest is from about 1/32 of an inch to about 3/6 of an inch, and this crest portion merges into ridge sides 32 that taper toward each other in a lateral outward direction with an included angle T of from about 2O degrees to about 120 degrees. The sides 32 of each ridge merge concavely into the root portion or bottom 30 of the groove 21 between intervening ridges, the radius of curvature U being from about of an inch to about 5/8 of an inch. |Such curved root portions 33 merge into the cylindrical bottommost portion 34 of the groove or root which has a at width W from about V16 of an inch to about 1 inch.

With a cutter made within the range of proportions set forth above, the grooves 11 and ridges 13 are formed in the highway surface that have a profile the reverse of the profile of the cutter ridges 20 and grooves 21; that is to say, the bottom or root portions 24 of the highway grooves will be curved corresponding to the curvature of the crest portions 31 of the cutters; whereas, the crest portions of the highway ridges will have a central ilat width B merging smoothly at opposite sides into convex curved surfaces 41 that form a portion of and also merge smoothly into the remaining portion of the sides 25 of the grooves or troughs formed in the concrete, the bottom 24 of the grooves or troughs being concavely curved, the configuration of the grooved concrete highway surface being illustrated most clearly in FIG. 6. Thus, the grooved portion of the highway has ridges 13 of extended Width separated by grooves 11 of a sucient depth as to carry off rain and other water and insure reflective paint surfaces on the sides 25 of the grooves eX- posed above the level of the rain water in the lower portions of the grooves.

There are no sharp corners in the concrete highway ridges 13, which causes them to possess great strength and a long and useful life. In addition, the absence of any sharp corners in the concrete ridges makes the grooves 11 therein self-cleaning, since dirt, salt, and road films do not tend to collect therein which would obliterate or eliminate the highway paint or other visible marking provided by or on the grooves 11 and ridges 13. Since the sides 25 of the grooves are tapered, highway paint placed thereon will be readily visible to the operators of motor vehicles traversing the highways. The highway grooves 11 themselves will give an audible indication to the vehicle operator that he is on or crossing the grooved or striped lane divider. However, he will still retain control of his vehicle since the essentially flat surface B on the crests of the ridges, when the vehicle tires pass over the grooved area, insures proper vehicle control. Because of the tapered sides 25 of the grooves 11 and the rounded regions 41, 24, ice collection and retention in the grooves is eliminated, since the ice forces itself up and out of the grooves as it forms and expands. It is only the crests 40 of the ridges 13 formed in the highway surface that are exposed to automobile tire wear, and such areas are only a minor portion of the entire painted area of the grooved highway stripe, being, for example, about 35% of the total painted area of the lane divider formed in the concrete. The absence of sharp corners, through the provision of the radiused longitudinal grooves and crest portions, enables reective beads in the highway paint to be placed in better fashion and retained on the groove and ridge surfaces, resulting in a brighter reective coating in the grooves 11 and on the ridges 13.

It will be noted that the ends 50 of the cutter terminate in half grooved regions, that is, grooves 21a extending about half the axial distance of a full groove 21 between ridges 20, and that the outer ends 51 of such partial end grooves are disposed radially inwardly of the innermost portions 34 of a full groove. Such grooved portions 21a also have a radius of curvature Y extending from the sides 32 of the ridge 20 which is greater than the radius of curvature U of the bottom portion of the grooves 21 between adjacent ridges. Such greater radius of curvature Y insures that the outenmost grooves 11 formed in the concrete will not terminate in a sharp corner with the adjacent highway surface 56, there being a curved corner or radius 5S at the outer side of the outermost groove. The greater radius of curvature Y at the ends of the cutters also provides for a curved or radiused run-out of the sidemost groove into the adjacent concrete surface in the event irregularities in the highway surface cause the cutter to move deeper thereinto than intended. Normally, the extent of penetration of the cutter 10 into the concrete surface is determined by a depth control sensing element, such as a rotating wheel or wheels (not shown) having a bearing shaft elevation fixed with respect to the center line of the arbor and shaft, such rotating wheel or wheels rolling along the highway surface. If the wheel were to move into a shallow depression in the highway surface, the cutter 10 could move deeper into the concrete surface than is actually required. However, with the radius of curvature Y at the endsv of the cutter being greater than the radius of curvature U between the sides and bottom portions or roots of the cutter, the deeper penetration of the cutter still results'in a curved corner 55 between the outer side of the outermost groove and the adjacent flat pave-ment surface 56.

FIG. 7 presents a cutter and its dimensions in inches, for purposes of example only. Such cutter produced grooves 11v in al concrete highway that were narrower in width 4than the width .of vthe intervening. ridges v1?, all surfaces merging smoothly intov oneV anothen. providing an absence of right, angle or other sharp corners, ,with the crests-40 vofi the concrete ridges lying Ain lessentially the same plane as the concrete highway sirface 56 on opposite sides thereof. Accordingly, the groovedfstripes effect no interference withsriowremoval equipment operating on the highway. y`We claimzvi v. 'ff- 1. In a millingcutter:.. a body adapted to be.v rotated about an axis, said body comprising axially spaced circumferential ridges extending around its peripheryy and disposed normal tothe body-axis, Asaid body having circumferential grooves-,between said ridges,-th'e bottoms of said grooves being of substantially greaterlaxial extent than the crests of said ridges, the bottoms ofsaid grooves comprising cutting means Afor Voperation upon the work being cut. Y l I 2. In a milling cutter as'de'tined inclaim. 1; at least a 3. In a milling cutter as defined in clairnl; said body having circumferentially spaced, longitudinal waterways extending through said ridges. f 4. In a milling cutter: av bodyadapted to be rotated about an axis, said body comprising axially spaced circumferential ridges extending around its periphery and disposed normal to the body axis, said body having circ'umferential grooves between said ridges, tlie bottoms of said grooves being of substantially greaterjjaxial extent than the crests of said ridges; cutting elements embedded in the crests of said ridges, and side cutting elements ernbedded in the sides of said ridges, said side cutting elements in confronting sides of said ridges being in opposed relation to each other for simultaneous op" ration upon the work being cut.

5.l In a milling cutter as defined in clainif.4; the sides of each rib tapering toward each other in the direction of the ridge crests. l 6. In a milling cutter as defined in claim 4;v and cutting elements embedded in the body at the bottoms of said grooves.

. 7. In a milling cutter as defined in claim 4; the sides of each rib tapering toward each other in the direction of the ridge crests, and cutting elements embedded in the body at the bottoms of said grooves.

' 8. In a milling cutter as defined in claim 4; the sides of each rib tapering toward each other in the direction of the ridge crests, the outer portion of the sides of each ridge being convexly curved and merging into the crest of said ridge, the inner portion of the sides of each ridge being concavely curved and merging into the bottoms of the grooves on opposite sides of each ridge, the central portion of the bottom of each groove between ridges being cylindrical.

9. In a milling cutter as defined in claim 4;v the sides of each rib tapering toward each other in the direction of the ridge crests, the outer portion of the sides of each ridge being convexly curved and merging into the crest of said ridge, the inner portion of the sides of each ridge being concavely curved and merging into the bottoms of the grooves on opposite sides of each ridge, the inner portions of the outer sides of the end ridges of said being concavely curved at a greater radius of curvature than the radius of curvature of the other concavely cured inner portion of said ridges.

10. `In a milling cutter as defined in clailm 1; the sides of each rib tapering toward each other in the direction of the ridge crests, the outer portion of the sides of each ridge being convexly curved and merging into the crest of ,said ridge, the inner portion of the sides of each ridge being concavely curved and merging into the bottoms of the grooves on opposite sides of each ridge, the inner portions of the outer sides of the end ridges of said body being concavely curved at a greater radius of curvature portion of the bottom of each groove 'being cylindrical.

than the radius of curvature of the other concavely curved inner portions of said ridges, the central portion of the bottom of each groove between ridges being cylindrical.

11. In a milling cutter as defined in claim 4; the sides of each rib tapering toward each other in the direction of the ridge crests, said body having circumferentially spaced, longitudinal waterways extending through said ridges.

l12. In a milling cutter as defined in claim 4; the sides of'each rib tapering toward each other in the direction of the ridge crests, said body having circumferentially spaced, longitudinal waterways extending through said ridges, the bottoms of each waterway being of undulant form and conforming generally to the shape of the crests and sides of said ridges and the bottoms of said grooves.

13. In a milling cutter as defined in claim 4; the sides of each rib tapering toward each other in the direction of the ridge crests, the outer portion of the sides of each ridge being convexly curved and merging into the crest of said ridge, theinner portion of the sides of each ridge being concavely curved and merging into the bottoms of the grooves on opposite sides of each ridge.

14. In a milling cutter as defined in claim 13; said convexly curved outer portions having a radius of curvature from about $5.2 inch to about 0716 inch, said concavely curved inner portions having a radius of curvature from about )A6 inch tofabout 5A; inch, the depths of each groove being from about 'SAG inch to about 1/2 inch, and the included angle between the tapered sides of each ridge being from about 2 0 degrees to about 120 degrees.

15. In a milling cutter as defined in claim 13; the central portion of the bottom of each groove between ridges being cylindrical, said convexly curved outer portions having a radius of curvature from about 19,2 inch to about 3/16 inch, said concavely curved inner portions having a radius of curvature from about 1/16 inch to about 5/8 inch, the depths of each groove being from about 3/16 inch to about 1/2 inch, and the included angle between the tapered sides of each ridge being from about 20 degrees to about 120 degrees, the axial extent of the cylindrical central portion being from about 1/16 inch to about 1A inch.

16. In a milling cutter as defined in claim 13; said convexly curved outer portions having a radius of curvature from about lyg inch to about 2%16 inch, said concavely curved inner portions having a radius of curvature from about 1/16 inch to about inch, the depths of each groove being from about 5716 inch to about 1/2 inch, and the included angle between the tapered sides of each ridge being from about- 20 degrees to about 120 degrees, cutting elements in the body at the bottoms of said grooves, said cutting elements being diamond cutting elements, said diamond cutting elements being spaced from each other and arranged in a predetermined pattern in said body.

17. In a milling cutter as defined in claim 13; the central portion of the bottovm of each groove between ridges being cylindrical, said convexly curved outer portions having a radius of curvature from about /g inch to about 9/16 inch, said concavely curved inner portions having a radius of curvature from about V16 inch to about 5/8 inch, the depths of each groove being from about 3/16 inch to about 1/2 inch, and the included angle between the tapered sides of each ridge being from about 20 degrees to about degrees, the axial extent of the cylindrical central portion being from about 1/16 inch to about 1A; inch, said cutting elements being diamond cutting elements, said diamond cutting elements being spaced from each other and arranged in a predetermined pattern in said body.

18. In a milling cutter: a body adapted to be rotated about an axis, said body comprising axially spaced circumferential ridges extending around its periphery and disposed normal to the body axis, said body having circumferential grooves between said ridges, the bottoms of said grooves being of substantially greater axial extent than the crests of said ridges; the sides of each rib tapering toward each other in the direction of the ridge crests,

diamond cutting elements embedded in the crests of said ridges, and side diamond cutting elements embedded in the sides of said ridges, said side diamond cutting elements in confronting sides of said ridges being in opposed relation to each other for simultaneous operation upon the work being cut, said diamond cutting elements being spaced from each other and arranged in a predetermined pattern in said body.

19. In a milling cutter as defined in claim 18; dialmond cutting elements in the body at the bottoms of said grooves, all of said bottom diamond cutting elements being spaced from each other and arranged in a predetermined pattern in said body.

20. In a milling cutter as defined in claim 18; the outer portion of the sides of each ridge being convexly curved and merging into the crest of said ridge, the inner portion of the sides of each ridge being concavely curved and merging into the bottoms of the grooves on opposite sides of each ridge, diamond cutting elements in the body at the bottoms of said grooves, all of said bottom diamond cutting elements being spaced from each other and arranged in a predetermined pattern in said body.

21. In a milling cutter as defined in claim 18; the outer portion of the sides of each ridge being convexly curved and merging into the crest of said ridge, the inner portion of the sides of each ridge being concavely curved and merging into the bottoms of the grooves on opposite sides of each ridge, diamond cutting elements in the body at the bottoms of said grooves, all of said bottom diamond cutting elements being spaced from each other and arranged in a predetermined pattern in said body, said body having circumferentially spaced, longitudinal waterways extending through sadi ridges, the bottoms of each waterway being of undulant form and conforming generally to the shape of the crests and sides of said ridges and the bottoms of said grooves.

References Cited UNITED STATES PATENTS 2,709,878 6/ 1955 Olson 299-39X 3,269,775 8/ 1966 Hatcher 299-39 3,306,669 2/ 1967 Christensen et al. 299-89 3,398,989 8/ 1968 Christensen 299-39 3,468,583 9/ 1969 Austin 299--89 ERNEST R. PURSER, Primary Examiner U.S. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION patent No, 3, 554 ,606 Dated January l2 1971 nventoms) Donald H. Mabey et a1.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as show-n below:

Column 5 line 63, after "said" insert body line 6 l'1" should read 4 Signed and sealed this 29th day of June 1971 (SEAL) Attest:

EDWARDM.FLETCHER,JR. WILLIAM E. SCHUYLBR, JR. Attestlng Offlcer Commissioner of Patents 

